feat(server): Add readOnly mode to Cursor provider for read-only operations

Adds a readOnly option to ExecuteOptions that controls whether the
Cursor CLI runs with --force flag (allows edits) or without (suggest-only).

Read-only routes now pass readOnly: true:
- generate-spec.ts, generate-features-from-spec.ts (we write files ourselves)
- validate-issue.ts, generate-suggestions.ts (analysis only)
- describe-file.ts, describe-image.ts (description only)
- generate-plan.ts, enhance.ts (text generation only)

Routes that implement features (auto-mode-service, agent-service) keep
the default (readOnly: false) to allow file modifications.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/server/src/routes/context/routes/describe-file.ts

@@ -207,6 +207,7 @@ File: ${fileName}${truncated ? ' (truncated)' : ''}`;
           cwd,
           maxTurns: 1,
           allowedTools: [],
+          readOnly: true, // File description only reads, doesn't write
         })) {
           if (msg.type === 'assistant' && msg.message?.content) {
             for (const block of msg.message.content) {

apps/server/src/routes/context/routes/describe-image.ts

@@ -371,6 +371,7 @@ export function createDescribeImageHandler(
           cwd,
           maxTurns: 1,
           allowedTools: ['Read'], // Allow Read tool so Cursor can read the image if needed
+          readOnly: true, // Image description only reads, doesn't write
         })) {
           if (msg.type === 'assistant' && msg.message?.content) {
             for (const block of msg.message.content) {